[S390] DEBUG_PAGEALLOC support for s390.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/Kconfig.debug b/arch/s390/Kconfig.debug
index 2283933..4599fa0 100644 (file)
--- a/arch/s390/Kconfig.debug
+++ b/arch/s390/Kconfig.debug
@@ -6,4 +6,12 @@ config TRACE_IRQFLAGS_SUPPORT
 
 source "lib/Kconfig.debug"
 
+config DEBUG_PAGEALLOC
+       bool "Debug page memory allocations"
+       depends on DEBUG_KERNEL
+       help
+         Unmap pages from the kernel linear mapping after free_pages().
+         This results in a slowdown, but helps to find certain types of
+         memory corruptions.
+
 endmenu

diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index 52b8342..1a2fdb6 100644 (file)
--- a/arch/s390/kernel/traps.c
+++ b/arch/s390/kernel/traps.c
@@ -271,7 +271,10 @@ void die(const char * str, struct pt_regs * regs, long err)
        printk("PREEMPT ");
 #endif
 #ifdef CONFIG_SMP
-       printk("SMP");
+       printk("SMP ");
+#endif
+#ifdef CONFIG_DEBUG_PAGEALLOC
+       printk("DEBUG_PAGEALLOC");
 #endif
        printk("\n");
        notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV);

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index b234bb4..983ec6e 100644 (file)
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -167,6 +167,33 @@ void __init mem_init(void)
               PFN_ALIGN((unsigned long)&_eshared) - 1);
 }
 
+#ifdef CONFIG_DEBUG_PAGEALLOC
+void kernel_map_pages(struct page *page, int numpages, int enable)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+       pmd_t *pmd;
+       pte_t *pte;
+       unsigned long address;
+       int i;
+
+       for (i = 0; i < numpages; i++) {
+               address = page_to_phys(page + i);
+               pgd = pgd_offset_k(address);
+               pud = pud_offset(pgd, address);
+               pmd = pmd_offset(pud, address);
+               pte = pte_offset_kernel(pmd, address);
+               if (!enable) {
+                       ptep_invalidate(address, pte);
+                       continue;
+               }
+               *pte = mk_pte_phys(address, __pgprot(_PAGE_TYPE_RW));
+               /* Flush cpu write queue. */
+               mb();
+       }
+}
+#endif
+
 void free_initmem(void)
 {
         unsigned long addr;

diff --git a/include/asm-s390/cacheflush.h b/include/asm-s390/cacheflush.h
index f7cade8..49d5af9 100644 (file)
--- a/include/asm-s390/cacheflush.h
+++ b/include/asm-s390/cacheflush.h
@@ -24,4 +24,8 @@
 #define copy_from_user_page(vma, page, vaddr, dst, src, len) \
        memcpy(dst, src, len)
 
+#ifdef CONFIG_DEBUG_PAGEALLOC
+void kernel_map_pages(struct page *page, int numpages, int enable);
+#endif
+
 #endif /* _S390_CACHEFLUSH_H */